Pulmonary metastases are common. They most frequently occur with tumours that have rich systemic venous drainage. Examples include renal cancers, bone sarcomas, choriocarcinomas, melanomas, testicular teratomas, and thyroid carcinomas. Most pulmonary metastases arise from common tumors such as breast, colorectal, prostate, bronchial, head and neck, and renal cancers. The detection of pulmonary metastases is crucial in the treatment of patients with cancer. Lymphangitis carcinomatosis is usually the result of hematogenous metastases to small pulmonary capillaries, with secondary invasion of peripheral pulmonary lymphatics. Retrograde extension from hilar or mediastinal nodes or direct invasion from diaphragmatic lymphatics is less common. Breast, lung, stomach, pancreas, and prostate cancers are the most common tumors that result in lymphangitis.